This invention relates in general to vinyl lined swimming pools and more specifically to a vinyl lined swimming pool coping system which extends about the periphery of the upper edge of a pool. More specifically, this invention pertains to a bullnose or concrete receptor type of swimming pool coping.
Bullnose or concrete receptor type copings are used when the deck for the pool is to be formed of concrete which is fast becoming one of the most frequently used types of swimming pool decks because of its many advantages.
In the past, bullnose or concrete receptor types of copings have been constructed of either extruded polyvinyl chloride (PVC) or extruded aluminium. There are many known examples such as those shown in U.S. Pat. Nos. 3,500,605; 3,546,720; 3,641,595; 3,811,236; 3,835,481; 3,938,199; 4,115,977; 4,124,907; and 4,167,084.
Of the two types of concrete receptor copings in wide-spread commercial use, PVC is sost widely used for a number of reasons. The advantages of PVC include the fact that it is more economical than aluminum. Also, unlike aluminum, it requires no painting and cannot be scratched or dented readily while being moved, stored or handled. Also because of its flexibility, it can be made to fit on radius (curved) panels used for forming kidney, and oval, shaped pools. The disadvantages of PVC include UV (ultraviolet light) degradation. Also the harsh freeze-thaw cycles experienced over much of the North American continent as well as other parts of the world, can have a devasting effect on PVC coping, causing it to yellow and possibly fail through cracking and breakage. When this happens, the cost of the coping itself is relatively minor, as the coping has a relatively low cost per linear foot, but the consequential damages arising from such a failure can be quite substantial.
To repair a damaged PVC coping, one must first drain the pool water which has normally been treated with expensive chemicals. Also the cost of the water required to fill a swimming pool in some rural areas can be very high because the water has to be trucked in. The next step is to remove the broken PVC coping which cannot be done until a section of the concrete decking approximately 1' wide about the periphery of the pool is broken with a jack-hammer and removed manually. At this stage the new coping is installed and the temporarily exposed bottom of the swimming pool must be touched up and cleaned thoroughly prior to the reinstallation of the vinyl liner providing that over the years the vinyl liner has not shrunk to the point where it is no longer possible to reinstall it. Should this shrinkage occur then the added expense of a new liner must be added to the expense of replacing the PVC coping.
Once the new coping has been installed and the vinyl liner hooked back into the new coping, the pool is ready for refilling. Then the final stage is to repair the concrete deck surrounding the pool. Simply adding new concrete between the newly installed coping and that portion of the concrete deck left unbroken can, and in most cases does, lead to adhesion problems between the old and new concrete. Therefore an expansion joint is normally used between the "old" and the "new" decks to eliminate this problem.
The final result of this repair is a two-tone deck consisting of new cement and weathered cement with an expansion joint separating the two. This is not asthetically acceptable to many people. Furthermore, the pool owner runs the risk of having the untouched or original portion of his concrete deck sink from lack of support due to the fact that under some circumstances the original concrete deck would have provided a bridge between the pool coping and the relatively compacted back-fill located the width of the coping back from the edge of the pool.
It will be appreciated that costs of this repair can be substantial and if costs are hindered by high water tables, a shrunken liner or problems with the weather, the costs can easily double or even triple under some circumstances.
Also in use are extruded aluminum concrete receptor copings. This type of coping is used by many manufacturers and pool builders because of the fact that it enables the vinyl pool liner to be held in position in a groove by a metal part which is generally less susceptible to breaking than plastic (PVC).
However aluminum concrete receptor copings have disadvantages. These include the fact that expensive packaging is required for these copings to protect their painted surfaces during the handling required for freighting and for storage. Also, once installed, this coping may require repainting on site due to scratches and nicks incurred in it over a period of time. Invariably, the resultant repainted surface will peel in a relatively short period of time. Also, the use of this type of coping on shaped pools such as those having a kidney-shape, oval-shape or round-shape is difficult if not impossible due to the necessity of forming a curve in the coping which usually resuts in the forming of an unacceptabe kink in the coping.
It is also known to employ a liner bead cover and/or a liner lock. This item can be installed when the pool is initially installed or the item can be retrofitted as a companion part to most types of copings no matter whether formed of aluminum or PVC. The function of a liner bead cover and liner lock is twofold. It locks the liner into place and prevents the bead (that portion of the vinyl liner which hooks into the coping) from popping out of its locked-in position which sometimes happens when the liner bead is not properly installed in its receptive groove. Bead cover or liner lock is only available in extruded PVC. The other function of a bead cover is to protect the soft flexible PVC bead against the ravages of UV exposure which may cause degradation leading to eventual failure of the bead. It does this simply by covering or shielding the bead portion of the liner from direct sunlight.